1. Field of the Invention
The present invention is directed to a programmable hearing aid, having an amplifier and transmission circuit that can be set to various transmission characteristics for altering its transmission properties between the microphone and earphone.
2. Description of the Prior Art
European Application 0 064 042 discloses a circuit arrangement for a hearing aid wherein the parameters for eight different ambient situations, for example, are stored in a memory in the hearing aid itself. By actuating a switch, a first group of parameters is retrieved and used to control the signal processor, connected between the microphone and earphone, via a control unit. This signal processor sets a first transmission function intended for a predetermined auditory environment. All eight transmission functions can be successively retrieved via the switch until that which is best suited at the moment has been found. Moreover, an automatic switching among permanently programmed transmission functions is provided when the user moves, for example, from a noisy environment into a quiet environment or vice versa. This switching also ensues cyclically (serially). When one wishes to set transmission functions other than the stored transmission functions, the non-volatile memory must be erased by an external programming unit and must be reprogrammed by the programming unit.
German OS 36 42 828 also discloses a remotely controlled, programmable hearing aid having an amplifier and transmission circuit that can be optionally set to different transmission characteristics for altering its transmission properties between the microphone and earphone. This known hearing aid has an external control device with a transmitter for the wireless transmission of control signals to the hearing aid, and a receiver located in the hearing aid for reception and demodulation of control signals. In this hearing aid, a base transmission characteristic is permanently set in the individual units of the transmission channel from the microphone to the earphone. Other transmission characteristics are stored in an external control device and can be optionally selected by actuating a switch or a push button and can be transmitted to the receiver provided in the hearing aid by the transmitter integrated in the external device. These signals received by the hearing aid serve--after demodulation and corresponding processing--the purpose of setting the different transmission characteristic of the hearing aid between the microphone and earphone for adaptation to one of a number of ambient situations stored in the external control device, for example in the form of control parameters. These control parameters are calculated from the audiogram of the wearer and from simulated ambient situations and are stored in the control device. The audiogram is thereby lost, i.e. it can no longer be reproduced. The same is true of the data representing the ambient situations. In particular, how these control parameters were calculated cannot be reconstructed after the calculation takes place.
German OS 32 05 685 discloses a hearing aid that can be programmed by the wearer, i.e., it can be set to his or her own hearing impairment and can be possibly reprogrammed given a change in the hearing impairment. To this end, the hearing-impaired person can successively retrieve a test program of test tones stored a memory in the hearing aid and the wearer can actuate a switch when the desired (appropriate) hearing threshold is reached, and thus effect the storing of a correction factor for the respective test tone. After storing these correction factors, a built-in microprocessor then calculates the valid transmission characteristic from the normal program stored in a memory and from the correction factors, this transmission characteristic being retained until the wearer reprograms the hearing aid in the same way. An adaptation to constantly changing ambient situations is thereby neither provided nor possible, not even by remote control.
German OS 39 00 588 discloses a remote control device for the wireless control of hearing aids, wherein the external remote control device contains a first memory for the acceptance and storing of audiometric data, a second memory for the acceptance of data identifying different ambient situations, and data processing means for calculating groups of control parameters from the audiometric data and from the data identifying the ambient situation according to one or more algorithms that are stored in a third memory in combination with the data processing means. Data allocated to the individual ambient situations can be respectively retrieved from the second memory using a keyboard, for calculating the corresponding group of control parameters. A microprocessor is provided in the external control device as the data processing means. The hearing aid can be programmed with the control parameters calculated in the control device, and thus can be permanently set for a specific ambient situation.